I do want to talk about top spin like I said before, but I have been thinking about this today - for the initial part of the short take back, would you say that you are trying to perform an external rotation of the shoulder with or without incorporating elbow movement? In the pro videos I linked in the thread plus others available, during their take backs I can't tell 100% if even the same player will always try to make the racquet follow a pendulum motion (approximately, and from external rotation of the shoulder) up with the elbow acting like the fixed point/pivot point (being stationary as much as possible, any motion backward is from body rotation), or if the elbow is being pulled back (elbow in the gut motion, going however much or little they want the elbow back) as external rotation of the shoulder still takes place. In short - as the racquet goes up and back during the initial part of the take back via the shoulder, should the elbow also help bring the racquet back and then down?

Also, even though this is not quoted, I'm gonna mention closed stance. I see Fed has it a lot in casual hitting, and I think I do it more when being casual too, but I have a feeling he opens up a lot more than I do in real play. It's just a habit of mine, but I think it also plays a part in limiting ssc - with a more open stance, you can load up the back/outside foot and twist the body, letting the uncoiling of the body whip the forehand around to contact. In my video, I'm seeing that I am facing sideways which is good, but have little to no coiling. I am going to work on coiling sideways instead of just facing sideways, I think that should help, right?

I don't understand what you're saying in the 1st paragraph. Are you sure you're talking about external shoulder rotation? Maybe you can word it differently.
Also this is addressed in the video on the site i told you about.

Yes you don't coil in your strokes. you just turn sideways. the shoulders should be turned more than the hips.
You should be getting power from the body and control from the arm. maybe about 70/30 or even 80/20 body/arm